Conductive tape for shoes



Oct. 4, 1960 R. w. PRICE 2,955,234

CONDUCTIVE TAPE FOR SHOES Filed Feb. 24, 1956 INVENTOR Russell W Price $Jh-J QIMM ATTORNEY United States Patent CONDUCTIVE TAPE FOR SHOES Russell W. Price, 11 Merton St., Newton, Mass. I Filed Feb. 24, 1956, Ser. No. 567,678

7 Claims. (Cl. 317-2) This invention relates to a conductive tape adapted to be attached to a shoe.

The invention has for an object to provide a novel and improved conductive tape which may be easily and quickly secured to any conventional shoe to provide a grounded connection between the body of the wearer and a grounded floor or surface to the end that static electric charges may be discharged harmlessly from the body through the conductive tape and into the grounded floor or other surface whereby the risk of explosion as the result of static sparks from the wearer may be reduced to a minimum.

With this general object in view and such others as may hereinafter appear the invention consists in the conductive.tape for shoes hereinafter described and particularly defined in the claims at the end of this specification.

In the drawings illustrating the preferred embodiment of the invention:

Fig. 1 is a perspective view of a shoe embodying the present conductive tape;

Fig. 2 is a bottom plan view of the shoe provided with the present conductive tape;

Fig. 3 is a cross sectional view taken on the line 33 of Fig. 2;

'Fig. 4 is a perspective view of one portion of the tape adapted to be secured to the outer sole of the shoe;

Fig. 5 is a perspective view of the portion of the strip adapted to be secured within the shoe for contact with the wearers foot; and

Fig. 6 is an enlarged side elevation of one end of the conductive strip illustrated in Fig. 5.

In general the present invention contemplates an electrically conductive tape adapted to be secured to a conventional shoe for use by persons in places where explosives or volatile liquids are present and which is particularly adapted for use by surgeons and other hospital personnel in an operating room having a conductive floor and where explosives, vapors and gases from volatile inflammable liquid anesthetics, such as ether, may be ignited by sparks produced by the discharge of static electrical charges built up in the body of the person. In practice the present conductive tape forms a conductive path for dissipating such dangerous static charges from the body of the wearer to the conductive floor with no danger of a spark. The present tape may also be used for shoes worn by persons in hazardous occupations, such as by personnel in munitions factories or other places using explosive gases or volatile materials.

The present conductive tape preferably comprises two strips or sections adapted to be connected together, one strip comprising a conductive rubber strip adapted to be attached to the bottom of the outer sole of a shoe for contact with the grounded floor or other surface, the second strip comprising a relatively thin conductive metal strip adapted to be attached within the shoe for contact :with the wearers foot, the conductive metal strip being extended over and around one side wall of the shoe and 2,955,234 Patented Oct. 4, 1960 electrically connected to the conductive rubber strip on the underside of the outer sole.

The relatively thin metal strip may and preferably will include a flexible conductive metallic foil laminated and reinforced with a relatively thin film or layer of plastic sheet material characterized by being difficult to tear and forming a tough reinforcement for the relatively thin metallic foil, such plastic lamination also providing a smooth clean surface which prevents soiling of the stockings worn by the person using a shoe having the present conductive tape installed therein.

An important feature of the present invention resides in the provision of a relatively thin and more or less rigid contact comprising a length of thin conductive metal, preferably a length of thin stainless steel connected to the inner end of the flexible metallic foil portion of the strip for contact with the wearers foot. The moisture of the foot caused by normal perspiration affords sufficient conductivity for dissipating dangerous electrostatic discharges from the body to the conductive floor. In practice a rela-' tively slow dissipation of the electrostatic charges is effected by the resistance factor inherent in the conductive rubber, such resistance factor varying from 60 thousand to 200 thousand ohms resistance.

Referring now to the drawings, 10 indicates generally a conventional shoe embodying the present conductive tape indicated generally at 12 and which includes a conductive rubber strip 14 attached to and preferably adhesively secured to the bottom of the sole of the shoe. A second strip preferably includes a thin flexible metallic conductive foil 16 electrically connected at one end to the conductive rubber strip 14, the other end being extended over one side wall of the shoe and then downwardly within the shoe and adhesively secured to the upper surface of the insole or other portion of the interior, such as the heel surface, the second strip embodying a relatively rigid metal contact =18 for engagement with the wearers foot.

As illustrated in Fig. 4, the conductive rubber strip 14 may and preferably will comprise a length of solid conductive rubber as distinguished from rubber covered cloth sheeting and having one side thereof provided with a previously applied bonding cement indicated at 20 which is dried thereon and which may be reactivated when ready for use to effect adhesion of the strip to the sole of the shoe or a similar pressure sensitive tape may be used. The strip 14 is preferably applied to the sole, as illustrated, with one end thereof secured to the sole at the elevated portion of the arch of the shoe immediately in front of the heel portion, the other end thereof being extended forwardly along the bottom of the sole and terminating short of the toe portion of the shoe as illustrated. The arch end of the conductive rubber strip 14 may be provided with the male portion 22 of a snap fastener as shown. In practice the solid conductive rubber strip 14 may be approximately 1 wide and 6" long and is preferably relatively thin, about of an inch in thickness for example, and is preferably rounded at its forward end so as to form a minimum obstruction on the bottom of the shoe.

The second strip 16 of the conductive tape preferably comprises a relatively thin, narrow strip of metallic foil, preferably a flexible conductive aluminum foil, having a thickness of about .002 of an inch and a relatively short length of stainless steel forming a contact 18 which may also be about .002 of an inch thick and secured in overlapping relation to the inner end of the foil strip 16 as illustrated. The other end of the foil strip 16 is provided with the female portion 24 of the snap fastener for connection to the male portion 22 thereof attached to the conductive rubber strip 14.

As best shown in Figs. 5 and 6, the relatively thin and flexible conductive aluminum foil is provided with a thin sheet plastic lamination 21, such as a polyester film sold under the trade name of Mylar, thus forming a tough reinforcing base for the metallic foil to prevent rupture under severe conditions of use. Another advantage of such lamination is that it provides a protective covering over the aluminum foil which prevents soiling of those portions of the stockings coming in contact therewith.

In order to conveniently attach the metallic strip 16 to the shoe the underside of the strip may be provided with an adhesive 26, preferably a pressure sensitive adhesive which, as herein shown, may be protected until ready for use by a protective covering or tape 28 which may be removed to expose the pressure sensitive adhesive on the underside of the strip when ready for use. In practice the conductive metal portion of the strip 16 may be about 7 of an inch in width and about 9" in length including the stainless steel contact 18. The contact 18 may be about 3 inches in length with one end thereof in overlapping relation and adhesively or otherwise secured to the end of the aluminum foil strip 16. The protective covering 28 preferably extends the full length of the strip 16 including the stainless steel contact 13, as shown. In practice the relatively thin metallic foil and stainless steel contact within the shoe does not cause any discomfort to the wearer.

In attaching the present conductive tape to a shoe, the surface of the sole to which the conductive rubber strip 14 is to be secured is first cleaned thoroughly with any suitable solvent whereupon a coating of bonding cement is applied to the cleaned portion. The conductive rubber strip 14 is then applied to the cement coated portion, the moist bonding cement serving to reactivate the dry cement coating on the underside of the conductive rubber strip providing a firm bond between the rubber strip and the outer sole of the shoe. The conductive rubber strip 14 is preferably located on the sole in the position shown in Fig. 2 with the male portion 22 of the snap fastener under the elevated portion of the arch and immediately in front of the heel. The protective covering 28 may then be removed from the underside of the conductive metal strip 16 to expose the pressure sensitive adhesive, and the female portion 24 of the snap fastener is then snapped over the male portion 22 to provide an electrical connection between the strips 14 and 16. The strip 16 is then extended substantially at right angles to the strip '14 across the arch portion of the sole and then upwardly along a side wall, preferably the outer side wall 30 adjacent the arch portion as shown. The flexible metallic strip 16 is then folded over and down the inner surface of the side wall 38 and is then extended transversely of the insole in a generally diagonal direction forwardly across the upper surface of the insole, as indicated in Fig. 1, so as to present the stainless steel contact 18 in a position to be engaged by the foot of the wearer. The strip may then be pressed into position to effect adherence thereof to the shoe by virtue of the pressure sensitive adhesive. The strip may likewise be extended over the insole of the heel area to be engaged by the heel of the wearer.

From the above description it will be seen that the present conductive tape provides a simple and economical expedient for quickly and easily converting a conventional pair of shoes into a pair of conductive shoes for use in an operating room or other place having a conductive floor and for the purpose of slowly dissipating electrostatic charges from the body through the tape and into the grounded floor, thus obviating the necessity for buying the relatively expensive shoes especially constructed for conductive purposes. The present conductive tape is relatively inexpensive and in practice may be expendable so that after being used while working in the operating room the tape may be removed from the shoe and discarded if desired. The present conductive tape is thus of particular advantage for use by visiting surgeons, internes, nurses, etc., providing a convenient and economical means for quickly converting their own shoes into conductive shoes. On the other hand it may be found more expedient for the user to convert an extra pair of shoes into conductive shoes in the manner above described to be used in the operating room.

While the preferred embodiment of the invention has been herein illustrated and described, it will be understood that the invention may be embodied in other forms within the scope of the following claims.

Having thus described the invention, what is claimed 1. In combination with a shoe, a conductive tape comprising a relatively narrow conductive rubber strip attached to the bottom of the outer sole of the shoe for contact with a grounded surface and having one end terminating at an elevated portion of the arch in front of the heel, said one end including one element of a separable fastener, and a relatively narrow, thin and flexible metal conductive strip having one end attached within the shoe for contact with the wearers foot, the other end having a cooperating element of said separable fastener and being extended outside the shoe and attached to said one element of said separable fastener in electrical contact with said conductive rubber strip, each of said strips being free of the heel portion of the shoe, the connected ends thereof being disposed at the elevated portion of the arch immediately in front of the heel.

2. In combination with a shoe, a conductive tape comprising a relatively narrow conductive rubber strip adhesively secured to the outer sole of the shoe for contact with a grounded surface and having one end terminating at an elevated portion of the arch immediately in front of the heel, said one end including one element of a separable fastener, an elongated relatively narrow metal foil conductive strip also adhesively secured to the shoe, one end of the conductive foil strip being extended within the shoe for contact with the wearers foot, the other end having a cooperating element of said separable fastener and being extended outside the shoe and detachably secured to said one element of said separable fastener in electrical contact with one end of said conductive rubber strip, each of said strips being free of the heel portion of the shoe, the connected ends thereof being disposed at the elevated portion of the arch immediately in front of the heel.

3. In combination with a shoe, a conductive tape comprising a relatively narrow conductive rubber strip adhesively secured to the outer sole of the shoe for contact with a grounded surface and having one end terminating at an elevated portion of the arch in front of the heel, said one end including one element of a separable fastener, an elongated relatively narrow metal foil conductive strip also adhesively secured to the shoe, one end of the conductive foil strip being extended within the shoe for contact with the wearers foot, the other end having a cooperating element of a separable fastener and being extended outside the shoe and detachably secured to said one element of said separable fastener in electrical contact with one end of said conductive rubber strip, said metal foil conductive strip having a thin, tough plastic reinforcing strip laminated to the outer face thereof, and the inner end of said strip having a relatively thin stainless steel contact secured thereto for engagement with the wearers foot.

4. In combination with a shoe having an insole and an outer sole, a relatively narrow conductive tape adapted to be attached to the shoe to convert the same to a. conductive shoe, said tape comprising an elongated and relatively narrow thin, solid conductive rubber strip adhesively secured to the bottom of the outer sole for contact with a grounded surface, said conductive rubber strip being extended substantially longitudinally of the sole with one end thereof disposed at the elevated portion of the arch immediately in front of the heel, said one end including one element of a separable fastener, an elongated metal foil conductive strip adhesively secured to the shoe, one end of said foil strip having a co operating element of said separable fastener and being detachably connected to and in electrical contact with said one end of the conductive rubber strip, the other end being extended substantially at a right angle to the rubber strip across the arch and around the side wall to within the shoe, said conductive foil strip having a tough plastic reinforcing film laminated to the outer face thereof, and the inner end thereof having a relatively thin stainless 'steel contact secured thereto, said contact end of the strip being extended transversely of the insole for contact with the wearers foot, each of said strips being free of the heel portion of the shoe.

5. A conductive tape as defined in claim 4 wherein said fastener comprises a metal snap fastener for detachably connecting the ends of the strips together in electrical contact.

6. A conductive tape adapted to be attached to a shoe to convert the same to a conductive shoe, said tape comprising a relative narrow conductive rubber strip adapted to be attached to the bottom of the outer sole for con- 6 tact with a grounded floor, a relatively narrow, thin, flexible, conductively metal strip adapted to be attached within the shoe for contact with the wearers foot and to be extended over one side wall of the shoe, and means for detachably securing the strips in end to end in electrical contact, said conductive metal strip comprising a metal foil conductive strip having a tough plastic reinforcing film laminated to one face thereof, and a stainless steel strip secured to the inner end thereof forming a contact for engagement with the foot, the other face of said strip having a coating of pressure sensitive adhesive, and a protective covering over said pressure sensitive adhesive capable of being peeled off to expose the adhesive prior to attaching the metal strip to the shoe.

7. A conductive tape as defined in claim 6 wherein the conductive metal strip and the stainless steel strip are relatively narrow and are approximately .002 of an inch in thickness.

References Cited in the file of this patent UNITED STATES PATENTS 497,822 Royer May 23, 1893 2,701,323 Lewis Feb. 1, 1955 2,745,041 Price May 8, 1956 2,785,344 Hines Mar. 12, 1957 

